Chang'e 6 lunar sample return mission returns with samples from moon's far side
theguardian.com
theguardian.com
https://youtu.be/wUju9-cckKA?si=nZFOCga10mnCA_vs
The other component is the autonomous docking of the return probe in lunar orbit.
Soviets have done a lunar sample return, but they had a probe that would lift off directly into a earth return trajectory, but that seems to have limited both the liftoff mass and the possible zones in moon from which it can lift off. This seems a much more complex mission than that.
Also some animated videos of the misson show a skip re-entry back to earth, don't know if it is the case during this particular flight.
Anyone building precision weapons has gotten fairly good at this.
If you've seen some of the Lunar or Martian landing videos, you'll notice that it's very hard to tell the scale. Especially on the Moon, the lack of atmosphere to disturb the surface makes it fractal-like, which probably really messes with the CV algorithm. It'd work fine when high up, but as you approach for landing, it would probably struggle, especially for, say, estimating how far away the surface is.
https://en.wikipedia.org/wiki/Kalman_filter
For distance during landing I would be thinking a spatially maximally distributed array of quartz-shielded, thermally-supported laser TOF sensors along nominal extremities, but that's just because they're familiar to me, small, power-efficient, highly linear, relatively accurate, and cheap. Unsure if the IC physics assumptions work in non-atmospheric conditions. Perhaps the output can be re-scaled to obtain cheap and accurate enough readings.
A non-dilettante with an actual physics degree would clearly be desirable ;)
The second sounds like bad process leading to bad input, at which point it becomes garbage in, garbage out. The workaround was untested and insufficient.
While you are of course correct the filter will not fix these, none of these are the fault of the filter, they are all human process issues that are firmly out of scope.
This one seem to use scaled down Soyuz capsule as reentry vehicle. They must have reused a lot of proven hardware and software unlike those.
Apparently cameras also have issues because the lack of atmosphere means everything is high contrast.
So basically, you don't actually know your altitude, and your visual systems may not be reliable.
https://robotics.jpl.nasa.gov/media/documents/DIMES-ai-space...
Martian winds make this more important there than on the Moon. The DIMES system integrates radar, visual images, and IMUs. They did not have a dedicated Doppler radar for horizontal velocity, for technical and cost reasons it was not workable.
From the introduction:
> Some of the challenges were subtler — and one in particular was subtle enough that it wasn’t fully appreciated until mission development was well underway.
> This was the challenge of martian winds. How to detect and compensate for them? In the worst-case scenario, they could tip the vehicle over in the final stages of descent such that the powered thrust intended to eliminate downward velocity might actually drive the platform sideways and down into the surface beyond the safety envelope of the airbag cushions.
> This article tells the story of how this late-understood challenge was addressed successfully — and, as it turned out, critically, for Spirit.
The system was improved and re-fielded for the successor missions - I think it goes under the name LVS now. One reference appears to be here: https://www-robotics.jpl.nasa.gov/what-we-do/applications/la...
Official announcement by the CNSA: https://www.cnsa.gov.cn/n6758823/n6758838/c10565180/content....
Congratulations for such an achievement!
In general I don't think people really appreciate how ridiculously little we know about everything outside of our planet. Like for instance it was only in 2013 (!!!) that it was discovered that Mars' soil is relatively 'moist', about 2% water by mass. And that's just the topsoil layer - it's suggestive that below the surface it could well be even more moist.
But the Moon's much closer, so we must know more, right? Well water ice on the Moon was only confirmed in 2018!! [1] So actually starting to get surface samples, and explore more of the Moon, ideally with a rapid return to humans on it is so exciting because who knows what we'll find out next? The unknown is precisely what makes exploring the unknown so enticing, rewarding, and fun!
[1] - https://www.space.com/41554-water-ice-moon-surface-confirmed...
Thats for surface water, we confirmed a while longer the moon has water underground.
In theory yes, in practice it's never the case, you have to justify hard why you want to do the experience and what you expect. Especially with multi million dollar experiences like these
Different bragging rights.
https://www.cnsa.gov.cn/english/n6465652/n6465653/c10523137/...
It is costly though to bring in a ton of <insert element> from the moon.
But then I do read and watch too much sci-fi!!
It could also be an abandoned base.
https://www.sciencedirect.com/science/article/pii/S254243512...
Takeaway: The samples indeed are very different.
The last sample reveals something about the surface of the moon.
The sample this time is from a big, deep hole created by a heavy hit which penetrated into the core of the moon, thus reveals the internals of the moon.
The issue has been that previous proposals have all been too complex and too expensive, eg, a second rover that has to retrieve the samples and then place them on a lander which has a rocket on-board, the rocket then launches back into orbit, where an orbiter picks up it up and brings it home.
They've recently started soliciting other ideas for a way it might be done from private industry. The most promising in my opinion being to use a Starship, so they would be able to send a large enough return rocket to not need an orbital rendezvous, significantly simplifying things. I doubt they're seriously proposing a crewed Starship sample retrieval just yet. Another neat proposal I've heard is to build on the success of the Ingenuity helicopter to have a bunch of similar helicopters go around picking up the samples instead of a rover.
Adding to the Mars Sample Return thing, apparently China just recently announced their intention to do it ~2030.
China has a plan to get an orbiting probe to Neptune but nothing about returning Mars samples. Highlights the different scale of the problem.
The initial plan for retrieval involved Roscosmos and ESA, but that's been called off for now. So they need some new plans. My favourite part of their initial sample return plan was the decision to not use a parachute to land it on earth, since they couldn't be sure one wouldn't fail.
https://www.nasa.gov/news-release/nasa-exploring-alternative... ("NASA Exploring Alternative Mars Sample Return Methods")
The latest Mars rover has an (IMHO, purely performative) function for collecting samples that, in theory, could be retrieved for Earth return by a separate lander in the future—one that hasn't been budgeted or designed yet.
https://en.wikipedia.org/wiki/Perseverance_(rover)#Samples_c...
https://en.wikipedia.org/wiki/International_Lunar_Research_S...
(nuclear power plans by Russia not so much)
Is there enough gravity on the moon to prevent the long-term health problems from the space station like bone, muscle and vision loss?
Why? Any lunar base without nuclear power plans is not a serious effort.
Giant radiators?
edit: fixed typo, derp. fusion=fission
I also meant to write fission in my original question, not fusion.
Radiators though, are constantly used in spacecraft, and seem to work well. Low gravity, no motion might let the thing be mostly the radiator, with not much support structure. Except it might need to be in shade, in the shadow of a building? hill? solar panels?
I wonder if recycling human liquid waste through evaporation could be of some use for that purpose.
Are you thinking of radioisotope generators? Those aren't reactors. They use thermocouples and need to get rid of the waste heat. The Voyager RTGs have radiator fins.
Yup, that's the thing on top [1].
Oversimplifiying: All new plnats have cooling towers, so the water they return to the environment is not too hot.
Maybe you could use helium or liquid sodium metal as the primary coolant, but then you still need to generate electricty via secondary water coolant loop that runs a steam-powered turbine. Really not plausible on the moon.
Or normal panels on the rim of Shackleton [1]. (You'd still want to bootstrap with fission.)
[1] https://en.wikipedia.org/wiki/Shackleton_(crater)#Potential_...
It's not serious with chemical propulsion and the Moon's day/night cycle. Put another way, if one team uses nukes and is, as a result, power unconstrained, while the other spends all its energy launching solar panels and batteries to keep life support online, it's obvious who's going to be doing any science.
> All reactors require coolant circulation and water is going to be among the most valuable commodities on the moon
Sodium and sterling, no water [1]. There is a reason even NASA is only seriously considering nuclear power [2].
[1] https://www.nasa.gov/directorates/stmd/tech-demo-missions-pr...
Even on earth, giant grid-scale storage system are not able to supply all the power for region they serve alone for more than some 4 or 6 hours. In the moon, they would have to supply power for some two weeks.
Battery storage is not a real solution on earth, it is even less plausible in the moon.
It's just that we're close enough to the Sun, and that a lot of us are living in low-density residences.
Solar ray density reduces to half of what we get on Earth on Mars our closest outer planet, simply from inverse square law. And deep space people always said it goes down so fast a space nuke is a hard requirement for Jupiter and beyond. There might be ways to make it work on Moon, but PV plus battery is just rural inner planets thing, not the way forward or anything. It's just temporary hype technology.
Sure, once you have two-week power-storage infrastructure. (And the scale to harvest a useful amount of energy once a month on average.) In the meantime, i.e. our lifetimes, you have countries that can build space nuclear reactors and countries being performative.
Beyond all this, I meant novel when I said novel. The regular extremes of heat and cold offer all sorts of interesting ideas. You've got room for predictable and endless convection on basically an arbitrarily large scale there. There is certainly going to be some clever way to exploit this in a novel fashion.
[1] - https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...
1. Batteries are heavy, and space ain't cheap. Current launch pricing is about $1.5k/kg to LEO. The Moon will be more, it's further away. Even if Starship brings that down by a factor of 10, transportations costs are still going to be astronomical.
2. The day-night cycle on the Moon is slow. Your batteries are going to need to be able to store half a month worth of power. You'll need 15x more batteries on the Moon than you would on Earth.
Otherwise the need to bring enormous power storage to handle the half month of darkness and bitter cold makes solar a bit impractical and the only other reasonable alternative is nuclear power.
The big problem with attempting to exploit the temperature differential is that it happens on such a slow cycle that the total amount of energy available is quite low.
Nobody knows. You might think scientist can science up answers to any question but it is impossible to know this without long term data which is simply not available.
There were some experiments done in parabolic flights [2] but those only last for a very short time.
There is this literature review [2]. They are not optimistic: "It can be anticipated that partial gravity environments as present on the Moon or on Mars are not sufficient to preserve all physiological systems to a 1 g standard if not addressed through adequate countermeasures." Which is space speak for "you will need to go to the gym on the moon". But they are willing to admit how little there is to know for certain: "The methodological quality of the vast majority of the available/included studies is too low to generate a compeling evidence."
1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10411353/
2: https://www.frontiersin.org/journals/physiology/articles/10....
To date, no mammals have given birth in space. We sent pregnant mice and had them return to Earth to give birth, and we've sent mouse zygotes and grown them in space, but no birth!
Or perhaps even the 2nd generation could be even more telling. Why not simply run the experiment until they all die off, or go full Malthus? Another interesting idea would be to create a faux terrarium type enclosure instead of a plain cage. Would the mice exhibit a bias towards the "ground"? And also it's kind of odd that none of the studies thought to include a lens wiper for their cameras after the first one demonstrated the problem. In 0g, various 'matter' ends up getting stuck on the camera lens, increasingly trending towards 0 visibility.
Generating these data is one of the biggest pay-offs of a lunar colony.
Is this one of those generational things like "on accident" vs. "by accident" or regional things like "math" vs. "maths"?
While it’s used interchangeably a lot, it’s also based on whether you have a scientific or CS background. My hunch is that the scientific plural usage will eventually largely die out except in very specific situations after a few generations given that software is eating the world.
[1] https://www.thesaurus.com/e/grammar/data-is-or-data-are/
"On accident": Abomination! Kill it with fire, now! </OldFartRant>
If you did have viable babies in low (not zero) gravity situations though, would you in fact be starting a new species.
* Like 100.000 years, probably more. (From the split of us from chimps 5.000.000 I counted like 30 species in https://en.wikipedia.org/wiki/Human_evolution , but the number depends a lot on who count them.)
* Isolate the populations so they can't interbreed (first because they can't meet and later becuse the dna is incompatible)